Going Green

Introduction
Medical Microbiology is the study of the causes and management of infectious diseases.
These can be caused by viruses, bacteria, micro fungi and protozoa. Medical Microbiology may overlap with parasitological, generally considered to be the study of diseases caused by Multicellular parasites. So, why do we need to know about microbiology? We are only 10% human. It has been estimated that there are about 1014 cells in the human body. Of these only 10% are of human origin. The remainders are the microbes that comprise our commensal flora. These are the microbes that live in and on our various body surfaces. We provide these organisms with food and shelter. In return, the commensal flora can play an important role in preventing infection. The word "commensal" means to share a table. The vast majority of commensal microbes are bacteria but we also harbor fungi and protozoa. Viruses are also found causing latent infections. These are infections where no symptoms are apparent. Most of the microbes that live on or in humans do no harm. Indeed, they may be positively beneficial. The relationship is, however, finely balanced. Microbes are continually probing our defenses and commensals that get into the "wrong" place can do untold damage. Peritonitis, for example is the life-threatening infection that results when gut microbes gain access to the peritoneal cavity, following a ruptured appendix. Urinary tract infections are most frequently caused when gut organisms or the skin flora gain access to the bladder.
A very small minority of microbes are primary pathogens. These are capable of infecting individuals and causing disease. Because infections are very common and may be life threatening, it is easy to get the wrong perspective on microbes. Without microbes, life on
Earth would not exist. They are responsible, for example for nutrient cycling. Certain Bacteria, for example, are the only organisms that can fix atmospheric nitrogen and make it available... [continues]

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